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How To Calibrate An Instant Read Thermometer

What good is a thermometer that doesn’t give you the correct reading?

01_NotCalibrated

This thermometer is off. No way is it almost freezing in my kitchen!

You need to calibrate, son!

When I worked on the grill of a busy restaurant, I had to stop (at least twice a shift) to recalibrate my thermometer. When a thermometer is in constant use, it starts to read off by one or two degrees Celsius (or five to ten Fahrenheit.)

Plus, it was an excuse to down a glass of iced water. Working on a grill is hot work.

Why calibrate?

Failing to re-calibrate is like not using a thermometer. I learned this one time when cooking a pork tenderloin roast. I’d learned my lesson. The temperature on the thermometer says it’s 125°F and the carryover cooking took it to 140°F, a perfect medium for the pork roast.

When I cut into the roast to serve it, it was raw. I felt like a donkey. (A little Gordon Ramsey for you there.)

Sure, the temperature read 125°F, but my thermometer was off by ten degrees. I should have calibrated it first.

How do I calibrate my thermometer?

Today I am going to show you how you can quickly calibrate your thermometer. All you need is a good thermometer, a glass, ice, and water. It will take less than a minute.

Yesterday I wrote about the top 6 thermometers I used in my career. I chose the most common thermometer out there for demonstration:



List Price: $9.99 USD
New From: $3.06 USD In Stock
Used from: Out of Stock

Here are the steps to take when you are calibrating a thermometer:

02_FindNut

Find the wrench that conveniently comes with this thermometer. It is on the side. If you are using a digital thermometer, disregard this step.

03_PutIn

Slide the stem through the hole…

04_UseWrenchMakeSureNutSecure

Place the hex nut in the wrench of the holder. Make sure it is secure.

05_HalfGlassIce

Fill a glass half-full with ice.

06_FillWater

Fill it with cold water.

07_RestThermFor6Seconds

Stick your stem into the glass. Your holder makes a convenient handle for you to hold over the water. Wait for six seconds so the needle stops. It should be at 0°C (or 32°F). If not, go on to the next step.

08_TurnKnobInDirectionYouNeed

Grab the top and move it like a dial while holding the wrench. You want to move it to 0°C (or 32°F).

09_TurnBelowPointYouWant

I like to move it slightly past where I need to, so I can correct it to be sure it is right where it needs to be.

10_TurnTo0C-Or32F

Here is the finished calibration. 0°C (32°F).

That’s how you calibrate your thermometer. A quick note: Some thermometers out there do not allow you to calibrate them. Throw them away and buy a nice one from the list I posted yesterday. Calibration should be easy to do, and take no time at all.

Your turn

When was the last time you calibrated your thermometer? Let me know in the comments.

Comments on this entry are closed.

  • John Paré

    Great advice that I have done on my thermometer. I could not agree more that cooking with a thermometer is the best way to cook.

  • Louis Gudema

    I had this thermometer and it was reading about 200 degrees in boiling water. Since we’re near sea level it should have been 212, so I tried your method. After calibrating in ice water it still read around 200 degrees in boiling water. So I calibrated it at 212 for the boiling water and then it read around 42 in ice water! So, basically, this is not the world’s greatest thermometer and you need to calibrate it for either high or low temps.

    I bought a better Taylor digital thermometer. It reads about 31.5 in ice water and 211 in boiling water. So it may be about .5-1 degree low, but it’s consistent at both ends of the scale.